Title: Accessing protected methods and properties out of context.
Question: Some times while developping a form it would be nice or it would be essential to have acces right away to protected methods and properties. Of course you can build a derived component that just publishes the methods you need. But for a single method call the overhead that this approach requires is often inapropriate.
What can we do instead?
Answer:
Here is an example.
I recently needed for proper operation access to the "change" method of a "spin edit" control (AmpPitchMaxSpinEdit). In the implementation section of the form (TCmnDispAmpSetDlg) I was developping, i simply redeclared the "spin edit" control (THelperSpinEdit). Then I type cast the forms "spin edit" controls to get acces to the method.
implementation
type
THelperSpinEdit=class(TSpinEdit);
function ExecuteCmnDispAmpSetDlg(aOwner:TComponent;
AmpVelMinMax:TAmpVelMinMax):Boolean;
begin
with TCmnDispAmpSetDlg.Create(aOwner) do begin
try
with AmpVelMinMax do begin
AmpPitchMaxSpinEdit.Value:=AmpPitchMax;
THelperSpinEdit(AmpPitchMaxSpinEdit).Change;
..........
Hope this note helps some time!